Dyno Results

[HighPSI]

Chuck,
I just dyno tuned Champions car Sunday. We had a similar problem. The car started to miss and showed a rich condition. The higher the boost, the worse it became. We are lenaing towards putting a MSD on it along with changing the valve springs.
FWIW: The car ran mid 9's and made 697rwhp with a 231" motor with the STOCK CRANK and RODS !! We never saw more than 38 psi of back pressure at 29 psi of boost (Q trim 74).

 

[BoostKillsStres]

Cal or Chuck,

What kind of A/F are you tuning for? I have a wideband on my car now with logging ability and would like to know what to shoot for. So far it seems to like 11.25-11.5:1 as when I shift to 3rd it dropped to ~11.7 and I had 3.8 knock. So I guess I need a little more fuel in the 4000 range where it lands after the shift and correct me if I'm worng but I'm thinking you want just enough fuel at the shift so as not to knock but also not make it too rich up through 4000 in 1st and 2nd, right???

TIA

 

[HighPSI]

You're on the right track.

 

[TurboTR]

Chuck- When you say it started to go fat, what was the actual a/f reading as it approached that rpm band? I think in general that spark engines start to misfire around the low 9's:1 range and richer. I've seen mine pretty well run in the mid/low 10's:1 measured range with the hose on at full boogie. But it still pulls pretty clean. OTOH with the stock ecm and 72's it would rich misfire and pop until I got the fuel curve turned down enough. I guess what I'm asking is, are you sure it's not a rich misfire as it passes through a few cells? FWIW that's pretty much what was happening to Austin Kendall's S2 car at the Buick v Ferd challenge this past year. Or maybe as the throttle is first whipped open, ie too much accel pump shot?

TurboTR